The invention relates generally to a rotatable cutter assembly. More particularly, the invention relates to a coupler for a rotatable cutter assembly. In one aspect of the invention, the rotatable cutter assembly can be a drill assembly such as, for example, a roof bolt drill assembly, such as used in underground mining operations, that utilizes the coupler of the invention.
Expansion of an underground mine such as, for example, a coal mine, requires digging a tunnel. Initially this tunnel has an unsupported roof. In order to support and stabilize the roof in an established area in an underground tunnel, bore holes are drilled in the roof. Typically, the apparatus used to drill these holes comprises a drill with a long shaft, i.e., drill steel, attached to a drill bit. The roof drill bit is detachably mounted, either directly or through the use of a chuck, to the drill steel at the distal end thereof. To commence the drilling operation, the roof drill bit is then pressed against the roof and the drilling apparatus is operated so as to drill a bore hole in the roof. The bore holes may extend between two feet to greater than twenty feet into the roof. These bore holes are filled with resin and roof bolts are affixed within the bore holes. A roof support, such as roof panels, is then attached to the roof bolts.
One problem associated with the drilling operation for drilling the bore hole into the roof of the mine is that a large amount of noise is generated. Studies have shown that, on average, drilling noise is the most significant contributor to a roof bolting machine operator's noise exposure. Thus, hearing loss remains one of the most common occupational illnesses for underground miners.
Another problem associated with the drilling operation for drilling the bore hole into the roof of the mine is mechanical failure of one or more of the various components of the roof bolt drill assembly that typically results from one or more factors, such as, for example, the mechanical forces encountered in the drilling operation and the rigid connections between the various components of the roof bolt drill assembly.
Thus, it would be desirable to have a rotatable cutter assembly and associated components, such as couplers, that overcomes the problems of known such assemblies and associated components, particularly for drill assemblies used in roof bolt drilling operations.